Urethane Casting

Low Volumes with Production-Level Quality

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Advantages of Urethane Casting

Durability

Polyurethane cast materials are available in rigid or flexible end-use plastics. Urethane cast parts are generally as tough or tougher than injection molded pieces, and are significantly stronger than 3D printed counterparts.

Scalability

Our casting process is optimal for low-volume production for quantities of one to several hundred. On average, a silicone mold can accurately cast about 20-25 parts. The maximum quantity varies based on part design and material cast.

Material Selection

We offer a wide range of rigid and flexible urethane cast materials, from very soft and flexible (Shore A) to extremely rigid and impact resistant (Shore D). Parts are cast in a color that is blended to your specifications.

Color Matching & Finishes

The urethane casting process is capable of reproducing small details. Little to no finishing is required, because the desired textures and finish levels are applied to the master pattern.

Rapid Turnaround

Urethane cast parts are shipped within 15 business days, depending on order specifications and volume. By contrast, injection molded parts can take months to build.

Urethane Casting Processes

Multi-Axis CNC Milling Centers

  • Parts up to 30" long
  • Shrinkage rate of + 0.15% is expected on all molds
  • Similar precautions to designing parts for SLA and Polyjet 3D printing should be taken when designing a part for urethane casting

Urethane Casting Materials

Plastics

  • Polyurethane (PU)
  • Silicone

Urethane Casting Finishes

Standard

Parts are built with a smooth, high-quality surface finish and your choice of color.

Custom

Xometry can provide additional processing, including custom texture and insert installation, to meet your needs.

Applications for Urethane Casting

Low-Volume Production

Urethane cast parts are perfect for low-quantity production — when volumes do not justify investment in injection mold tooling — as well as for first run production parts, which can be completed weeks before production tooling is ready.

Advanced Prototyping

The urethane casting process and relatively inexpensive tooling involved makes it easy and economical to make any necessary design changes. Additionally, different materials can be used with the same mold, making it possible to test designs with a variety of materials.

Market Testing

End-user functionality and a high-quality finish makes urethane cast parts ideal for consumer testing, user evaluation and concept models. Using the cast urethane process means that changes can be incorporated quickly for either further testing or market launch.

Overview: What is Urethane Casting?

The Basics of Urethane Casting

Urethane casting provides end-use, rigid or flexible, plastic parts with production-level quality. Built without expensive and time-consuming hard tooling, the urethane casting process uses a 3D-printed master pattern and silicone mold to deliver high-quality, short-run parts in a fraction of the time and a fraction of the cost of injection molding.

How Urethane Casting Works

Urethane casting is similar to injection molding in that liquid plastic is poured into a mold of the final part. The major difference is that urethane casting uses a "soft" mold made of silicone whereas injection molding using a "hard" mold that has been CNC machined. The drawback to urethane casting, then, is that the mold wears out more quickly. However, it is vastly more cost-efficient for low-volume and prototype plastic parts with production-level quality and surface finishes.

The urethane casting process has 3 major steps:

The Master Pattern: In step one, a master pattern of the final part is made using an additive manufacturing process. Polyjet 3D or stereolithography (SLA) 3D printing processes are most often used due to the high-resolution and naturally smooth finish to the prints.

Molding: In step two, the 3D printed master pattern is encased in liquid silicone to form an accurate mold. Multiple molds can be made from the same master pattern which makes urethane casting perfect for on-demand, low-volume production runs. When the mold cures, it is cut into distinct halves and the master pattern is removed.

Pouring: In the final step of the urethane casting process, liquid plastic is poured into the silicone mold, and the mold is then placed in a vacuum chamber, which helps remove air bubbles in the liquid material. Once cured, the silicone halves are separated and the newly formed part is removed. This process is repeated until the desired quantity is achieved.

Benefits of Urethane Casting

Urethane casting has a low-cost and quick turnaround for high-quality plastic parts compared to that of injection molding or 3D printing. Where injection molding requires expensive up-front investment for the machining of the mold, urethane casting's silicone mold is inexpensive and easy to produce off the master pattern. Where most 3D printing processes require extensive post-processing to get to a near-finished state, a urethane cast part comes out of the mold ready to go with just a few minutes of clean up. Urethane casting is the go-to solution when looking to do on-demand prototyping or low-volume production of rigid, flexible, clear, colored, or even rubber-like plastic parts. It's truly a jack of all trades process.

The Benefits of Working With Xometry For Urethane Casting

Xometry supports any urethane casting process, material or finish you could need. Our extensive network of SLA and Polyjet 3D printing partners means we can handle everything from the master pattern and mold-making, to the production casting of parts and custom finishes. With more than 2,400 vetted manufacturing partner facilities across the U.S., Xometry is able to pair your part order with the machine shop best suited to handle the quality, surface finishes, performance, and color requirements you need — resulting in competitive prices and ideal lead times for your projects.

Featured Urethane Casting Resources

Three Benefits of Urethane Casting

Three Benefits of Urethane Casting

Whether you’re a Fortune 500 company or a start-up looking to beat your competitor to market, striking the right balance between high-quality, end-use parts and production lead-time can be a headache.

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